(57d) Encapsulation of Lactic Acid Bacteria By Multiple Emulsion System

In this study, we prepared functional food powder by multiple emulsions, which contained lactic acid bacteria with spray drying process. Generally, the functional food with the probiotic bacteria provides beneficial health effects, especially for digestive system. However, LAB has sensitive characteristics and is liable to damage under harsh and detrimental conditions no matter it exists in human digestive system or circulation storage. In order to maintain the viability of probiotic bacteria during processing and storage afterwards, encapsulation of probiotic bacteria by multiple emulsions was introduced for development of value-added product. Multiple emulsions are really complex with both coexistence of water-in-oil (W/O) and oil-in-water (O/W). They can be classified into two major types: water-oil-water emulsion (W/O/W) and oil-water-oil (O/W/O). In this study, W/O/W emulsion type was prepared for consideration of application potency in the future. Thanks to the multi-compartmentalized structure, multiple emulsions can prevent the functional components from environmental damage as result of masking flavor or releasing control. So as to meet the above requirements, we selected higher heat-tolerant lactic acid bacteria as encapsulated target through food–grade W/O/W multiple emulsions by a two-stage process.

To design the targeting formulation, edible proteins and polysaccharides were used in extra water phase as excipients. The survival rate of lactic acid bacteria and recovery efficiency were evaluated during the process. The survival rate of encapsulated lactic acid bacteria with stimulation of gastrointestinal conditions was also studied. The results clearly showed that the viable cell count of multiple emulsions had a marked increase along with formulation design. The viable probiotic cells obtained from emulsion was around 5.8×10⁸ CFU/mL and 8.1×10⁷ CFU/g after spray drying. The decreased amount of encapsulated lactic acid bacteria was less than 1 order of magnitude for viability assay under simulated gastrointestinal conditions. On the contrary, the free cells showed a higher decrease in their viability under same conditions (> 5 log CFU/g). The results obtained in this study suggested that multiple emulsions could play as a good delivery system and provide good protection for lactic acid bacteria and extend its chemical stability.